Commit 5dc30558 authored by Don Zickus's avatar Don Zickus Committed by Ingo Molnar
Browse files

x86, NMI: Add back unknown_nmi_panic and nmi_watchdog sysctls 



Originally adapted from Huang Ying's patch which moved the
unknown_nmi_panic to the traps.c file.  Because the old nmi
watchdog was deleted before this change happened, the
unknown_nmi_panic sysctl was lost.  This re-adds it.

Also, the nmi_watchdog sysctl was re-implemented and its
documentation updated accordingly.

Patch-inspired-by: default avatarHuang Ying <ying.huang@intel.com>
Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Reviewed-by: default avatarCyrill Gorcunov <gorcunov@gmail.com>
Acked-by: default avatarYinghai Lu <yinghai@kernel.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 96a84c20

Documentation/kernel-parameters.txt

+1 −9
Original line number Diff line number Diff line
@@ -1579,20 +1579,12 @@ and is between 256 and 4096 characters. It is defined in the file 


	nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels

			Format: [panic,][num]

			Valid num: 0,1,2

			Valid num: 0

			0 - turn nmi_watchdog off

			1 - use the IO-APIC timer for the NMI watchdog

			2 - use the local APIC for the NMI watchdog using

			a performance counter. Note: This will use one

			performance counter and the local APIC's performance

			vector.

			When panic is specified, panic when an NMI watchdog

			timeout occurs.

			This is useful when you use a panic=... timeout and

			need the box quickly up again.

			Instead of 1 and 2 it is possible to use the following

			symbolic names: lapic and ioapic

			Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic



	netpoll.carrier_timeout=

			[NET] Specifies amount of time (in seconds) that

arch/x86/kernel/apic/hw_nmi.c

+0 −3
Original line number Diff line number Diff line
@@ -99,6 +99,3 @@ static int __init register_trigger_all_cpu_backtrace(void) 
}

early_initcall(register_trigger_all_cpu_backtrace);

#endif
 


/* STUB calls to mimic old nmi_watchdog behaviour */

int unknown_nmi_panic;

arch/x86/kernel/traps.c

+11 −5
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ EXPORT_SYMBOL_GPL(used_vectors); 


static int ignore_nmis;



int unknown_nmi_panic;



static inline void conditional_sti(struct pt_regs *regs)

{

	if (regs->flags & X86_EFLAGS_IF)
@@ -300,6 +302,13 @@ gp_in_kernel: 
	die("general protection fault", regs, error_code);

}



static int __init setup_unknown_nmi_panic(char *str)

{

	unknown_nmi_panic = 1;

	return 1;

}

__setup("unknown_nmi_panic", setup_unknown_nmi_panic);



static notrace __kprobes void

mem_parity_error(unsigned char reason, struct pt_regs *regs)

{
@@ -371,7 +380,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs) 
			reason, smp_processor_id());



	printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");

	if (panic_on_unrecovered_nmi)

	if (unknown_nmi_panic || panic_on_unrecovered_nmi)

		panic("NMI: Not continuing");



	printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
@@ -397,11 +406,8 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs) 
		if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)

							== NOTIFY_STOP)

			return;



			unknown_nmi_error(reason, regs);

#else

		unknown_nmi_error(reason, regs);

#endif

		unknown_nmi_error(reason, regs);



		return;

	}

kernel/sysctl.c

+16 −0
Original line number Diff line number Diff line
@@ -745,6 +745,22 @@ static struct ctl_table kern_table[] = { 
		.extra1		= &zero,

		.extra2		= &one,

	},

	{

		.procname       = "nmi_watchdog",

		.data           = &watchdog_enabled,

		.maxlen         = sizeof (int),

		.mode           = 0644,

		.proc_handler   = proc_dowatchdog_enabled,

	},

#endif

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)

	{

		.procname       = "unknown_nmi_panic",

		.data           = &unknown_nmi_panic,

		.maxlen         = sizeof (int),

		.mode           = 0644,

		.proc_handler   = proc_dointvec,

	},

#endif

#if defined(CONFIG_X86)

	{

kernel/sysctl_binary.c

+0 −1
Original line number Diff line number Diff line
@@ -136,7 +136,6 @@ static const struct bin_table bin_kern_table[] = { 
	{ CTL_INT,	KERN_IA64_UNALIGNED,		"ignore-unaligned-usertrap" },

	{ CTL_INT,	KERN_COMPAT_LOG,		"compat-log" },

	{ CTL_INT,	KERN_MAX_LOCK_DEPTH,		"max_lock_depth" },

	{ CTL_INT,	KERN_NMI_WATCHDOG,		"nmi_watchdog" },

	{ CTL_INT,	KERN_PANIC_ON_NMI,		"panic_on_unrecovered_nmi" },

	{}

};

CRA Git | Maintained and supported by SUSTech CRA and CCSE